Method for destruction of pyrotechnic waste

ABSTRACT

A method for combustion of pyrotechnic waste which involves controlled burning of the waste in an incinerator with scrubbing of the smoke and fumes produced.

United States Patent Altekruse Sept. 9, 197 5 METHOD FOR DESTRUCTION 0F 3,195,608 7/1965 Voorheis et al. 110/18 x PYROTECHNIC WASTE 3,452,690 7/1969 Tarbox et al. 1 10/7 3,848,548 11/1974 Bolejack, Jr. et al 1 10/7 [75] Inventor: Richard D. Altekruse, Herrin, Ill.

73 A :Ol'C t',NH I sslgnee 52 orpora [on ew ave Primary ExaminerKenneth W. Sprague Attorney, Agent, or FirmDonald R. Motsko; William [22] Filed: Nov. 13, 1974 W. Jones [21] Appl. No.: 523,611

[52] U.S. Cl 110/18 R; llO/7 R; llO/lOl C [57] ABSTRACT [51] Int. Cl. F23G 7/00; F23K 3/00 Field of Seal'dl 7 8 R, 8 18 A method for combustion of pyrotechnic waste which 1 1O/ 101 R, 1 C involves controlled buming of the waste in an incinerator with scrubbing of the smoke and fumes produced. [56] References Cited UNITED STATES PATENTS 6 Claims, 1 Drawing Figure 2,354,747 8/1944 Epstein et al. 110/7 n y c c C 1 l t /8 Z6 Z o o o o o o o o L o o o o o o o o a M METHOD FOR DESTRUCTION PYROTECHNIC WASTE 1 This invention relates to a method for disposing of pyrotechnic scrap or waste material by controlled combustion which is safe and non-polluting to the environment.

The manufacture of pyrotechnic devices such as flares and the like results in generation of scrap and waste pyrotechnic material which cannot be refined and must be disposed of. This waste material is mostly magnesium plus sodium nitrate with some of it including a resinous binder. The waste material varies in consistency from a fine sand to large lumps which can be broken down for disposal.

Previously, this material was disposed of by merely dumping it in a pond or the like, or by wetting it with furnace oil and burning it outdoors. The ignition temperature of the material is about 600F and it burns at a temperature exceeding about 5,000F. The products of combustion are about 73 percent MgO and balance sodium oxide with traces of carbon dioxide and water vapor. Theseproducts appear in a dense white smoke or fume which is persistent.

With the recent interest in preserving the quality of the environment, the previously acceptable methods of disposing of this pyrotechnic waste are presently unacceptable and even illegal in many states.

This invention provides an environmentally acceptable method for controlled incineration of pyrotechnic waste material. The waste material is burned in a closed incinerator and the resultant smoke and fumes are cleaned by conventional methods in a stack. The incinerator is lined with conventional refractory material and has an opening in its top through which charges of the pyrotechnic material are introduced. The burning is in a step-wise fashion, i.e. a charge of predetermined weight is dropped into the incinerator and is incinerated as it falls through the incinerator. The next charge to be burned is dropped into the incinerator only after the preceeding charge has been completely burned. The bottom of the incinerator is covered with incandescent coke which provides the heat needed to ignite the charges and which also insulates the refractory forming the bottom of the incinerator from the heat generated by the burning pyrotechnic charge, thus providing acceptably long life for the lining of the incinerator. A conveyor belt may be used for transporting and dumping successive charges into the incinerator. The incinerator will continue to operate as long as the coke bed remains incandescent. Detectors can be used to monitor the coke bed and to ascertain ignition and combustion of each charge of pyrotechnic material. The detectors can operate to shut off the conveyor belt should either condition not be detected.

It is, therefore, an object of this invention to provide a method for the incinerating of pyrotechnic waste which is non polluting to the environment.

It is a further object of this invention to provide a method of the character described wherein the incineration proceeds within a refractory lined chamber.

It is yet another object of this invention to provide a method of the character described wherein the refractory is protected from the high heat of combustion generated by the burning pyrotechnic waste.

These and other objects and advantages of the method of this invention will become more readily apparent from the following detailed description of the invention taken in conjunction with the accompanying drawing which is a relatively schematic representation, in cross-section, of an incinerator adapted to perform the method of this invention.

Referring to the drawing, there is disclosed an incinerator 2 made of refractory brick and having a cubical or cylindrical shape. The bottom wall 4 of the incinerator is sloped downwardly and inwardly at an angle of about 45 to a centrally located sump 6. A foundation 8 closes off the bottom of the sump 6. The bottom wall 4 of the incinerator is preferably constructed so as to be blast-proof. A plurality of draft ducts 10 extend into the sump 6 and may be closed with doors 12. An access opening 14 which may be closed with a door 16 is disposed in the side wall adjacent the bottom wall for charging the incinerator with fuel and for cleaning out the incinerator. A plurality of air admission ports 18 are formed in the side wall of the incinerator. A flue 20 of internally insulated sheet steel is disposed in the top wall of the incinerator and is equipped with a blower and fume scrubber (not shown). A charging port 22 is disposed in the center of the incinerator top wall and is preferably just large enough to pass a charge of material to be incinerated. A charge of fuel in the form of coke 24 is disposed in the bottom of the incinerator and preferably covers the bottom wall 4 and fills the sump 6. An infra-red radiation cell 26 is focussed on the coke bed and an ultra-violet cell 28 is focussed on the center of the incinerator chamber. A conveyor 30 is disposed above the incinerator and is powered by an electric motor 32. The infra-red cell 26 is connected to the motor 32 so that the conveyor 30 cannot be operated unless the coke bed 24 is incandescent. The ultra-violet cell 28 is connected to a timer 34 which resets itself to zero each time a combustion flash is detected by the cell 28, and the timer 34 is in turn connected to the electric motor 32. In this manner the conveyor will be shut off by the timer if no ignition flash is detected by the ultra-violet cell 28.

As will be readily seen, charges C of pyrotechnic waste material of predetermined weight are placed on the conveyor 30 at spaced intervals and transported to the incinerator charging port 22 where they fall from the conveyor into the incinerator. As the charge C falls through the incinerator it approaches the incandescent coke bed and is heated thereby. When the temperature around the descending charge reaches its ignition point, the charge ignites and burns in a ball of flame. The size of the incinerator is selected so as to ensure that the side and top walls of the incinerator are not touched by the fire ball and are thus not prematurely broken down during incineration of the pyrotechnic material. The bottom wall of the incinerator is insulated against the fire ball temperature by the incandescent coke. The smoke and fumes produced by burning the pyrotechnic material are drawn out through the stack 20 and are scrubbed therein in a conventional a failure of a charge to burn, or when the fuel bed ceases to be incandescent.

Since many changes and variations of the disclosed embodiment of the invention may be made without departing from the inventive concept, it is not intended to limit the invention otherwise than as required by the appended claims.

What is claimed is:

1. A method of incinerating pyrotechnic material which has a combustion temperature of about 5,000F or greater, said method comprising the steps of:

a. providing an incinerator having top, bottom and side walls, and a stack including pollution controls therein;

b. providing an incandescent fuel bed on said incinerator bottom wall, said fuel bed overlaying at least a portion of said bottom wall to insulate the latter against heat generated by combustion of a charge of the pyrotechnic material;

c. dropping a charge of pyrotechnic material or predetermined size through said incinerator;

d. igniting said charge of pyrotechnic material as it falls through said incinerator to produce a fireball the periphery of which does not touch said top and side walls of said incinerator; and

e. passing gaseous products of combustion of said fireball through said stack.

2. A method of incinerating charges of pyrotechnic material having a combustion temperature of about 5,000F or greater, which charges are formed so as to produce a fireball, when incinerated, of predetermined size, said method comprising the steps of:

a. providing an incinerator having top, bottom and side walls, and a. stack including pollution controls therein;

b. providing an incandescent fuel bed on said incinerator bottom wall, said fuel bed overlaying at least a portion of said bottom wall to insulate the latter against heat generated by combustion of the pyro technic material;

c. dropping a preformed charge of pyrotechnic mate rial through said incinerator and igniting said dropping charge of pyrotechnic material as it falls through said incinerator to form a fireball of the predetermined size; and

d. said incinerator being of a size wherein said fireball does not contact said incinerator top and bottom walls during combustion of said charge.

3. A method of incinerating charges of pyrotechnic material having a combustion temperature of about 5,000F or greater, which charges are formed so as to produce a fireball, when incinerated, of predetermined size, said method comprising the steps of:

a. providing an incinerator having top, bottom and side walls, and a stack including pollution controls therein;

b. providing an incandescent fuel bed on said incinerator bottom wall, said fuel bed overlaying at least a portion of said bottom wall to insulate the latter against heat generated by combustion of the pyrotechnic, said fuel bed providing an ignition zone for the pyrotechnic material, which ignition zone is within the incinerator and upwardly spaced from said fuel bed;

c. dropping a preformed charge of pyrotechnic material through said ignition zone to ignite the charge while the latter is dropping through said incinerator to form a fireball of predetermined size; and

said incinerator being of a size large enough to prevent said fireball from contacting said top and side walls during combustion of said charge.

4. The method of claim 3, further comprising the steps of providing driven conveyor means for conveying separate charges of pyrotechnic material to said incinerator for introduction therein, and dumping said charges into said incinerator at spaced intervals so that a charge does not enter said incinerator until 'after the preceding charge has been incinerated.

5. The method of claim 3, further comprising the steps of focussing an infra-red detector on said fuel bed and operably connecting said detector to said conveyor means to prevent the latter from operating unless said fuel bed is incandescent.

6. The method of claim 3, further comprising the steps of focussing an ignition detector on said ignition zone and operably connecting said detector to said conveyor means to interrupt operation of the latter when no ignition of a dropped charge of pyrotechnic material is detected. 

1. A method of incinerating pyrotechnic material which has a combustion temperature of about 5,000*F or greater, said method comprising the steps of: a. providing an incinerator having top, bottom and side walls, and a stack including pollution controls therein; b. providing an incandescent fuel bed on said incinerator bottom wall, said fuel bed overlaying at least a portion of said bottom wall to insulate the latter against heat generated by combustion of a charge of the pyrotechnic material; c. dropping a charge of pyrotechnic material or predetermined size through said incinerator; d. igniting said charge of pyrotechnic material as it falls through said incinerator to produce a fireball the periphery of which does not touch said top and side walls of said incinerator; and e. passing gaseous products of combustion of said fireball through said stack.
 2. A method of incinerating charges of pyrotechnic material having a combustion temperature of about 5,000*F or greater, which charges are formed so as to produce a fireball, when incinerated, of predetermined size, said method comprising the steps of: a. providing an incinerator having top, bottom and side walls, and a stack including pollution controls therein; b. providing an incandescent fuel bed on said incinerator bottom wall, said fuel bed overlaying at least a portion of said bottom wall to insulate the latter against heat generated by combustion of the pyrotechnic material; c. dropping a preformed charge of pyrotechnic material through said incinerator and igniting said dropping charge of pyrotechnic material as it falls through said incinerator to form a fireball of the predetermined size; and d. said incinerator being of a size wherein said fireball does not contact said incinerator top and bottom walls during combustion of said charge.
 3. A method of incinerating charges of pyrotechnic material having a combustion temperature of about 5,000*F or greater, which charges are formed so as to produce a fireball, when incinerated, of predetermined size, said method comprising the steps of: a. providing an incinerator having top, bottom and side walls, and a stack including pollution controls therein; b. providing an incandescent fuel bed on said incinerator bottom wall, said fuel bed overlaying at least a portion of said bottom wall to insulate the latter against heat generated by combustion of the pyrotechnic, said fuel bed providing an ignition zone for the pyrotechnic material, which ignition zone is within the incinerator and upwardly spaced from said fuel bed; c. dropping a preformed charge of pyrotechnic material through said ignition zone to ignite the charge while the latter is dropping through said incinerator to form a fireball of predetermined size; and d. said incinerator being of a size large enough to prevent said fireball from contacting said top and side walls during combustion of said charge.
 4. The method of claim 3, further comprising the steps of providing driven conveyor means for conveying separate charges of pyrotechnic material to said incinerator for introduction therein, and dumping said charges into said incinerator at spaced intervals so that a charge does not enter said incinerator until after the preceding charge has been incinerated.
 5. The method of claim 3, further comprising the steps of focussing an infra-red detector on said fuel bed and operably connecting said detector to said conveyor means to prevent the latter from operating unless said fuel bed is incandescent.
 6. The method of claim 3, further comprising the steps of focussing an ignition detector on said ignition zone and operably connecting said detector to said conveyor means to interrupt operation of the latter when no ignition of a dropped charge of pyrotechnic material is detected. 